Electric space heater

ABSTRACT

An electric space heater having a sinusoidal heating element connected to mirror image portions of a reflector formed of sheet metal and having a substantially uniform parabolic crosssectional configuration throughout its length. The central portion of the reflector is connected to the space heater housing while the top and bottom mirror image portions of the reflector are free to flex in response to heating of the heating element. The space heater includes a protective grill positioned in front of the heating element, which grill is rigidly secured to a base portion and top cover member of the space heater without the use of external fastening means.

United States Patent us] 3,637,981 Swimmer [451 Jan. 25, 1972 54ELECTRIC SPACE HEATER 3,062,945 11/1962 Glynn ..2l9/357 X 3,069,52512/1962 Waters ..2l9/347 X [72] Inventor: James A. Swimmer, HighlandPark, Ill. [73] Assign: Ben" Comomhn Primary Examiner-R. F. StaublyGough ..2l9/347 X Attorney-Lettvin and Gerstman [57] ABSTRACT Anelectric space heater having a sinusoidal heating element connected tomirror image portions of a reflector formed of sheet metal and having asubstantially uniform parabolic cross-sectional configuration throughoutits length. The central portion of the reflector is connected to thespace heater housing while the top and bottom mirror image portions ofthe reflector are free to flex in response to heating of the heatingelement. The space heater includes a protective grill positioned infront of the heating element, which grill is rigidly secured to a baseportion and top cover member of the space heater without the use ofexternal fastening means.

8 Claims, 7 Drawing Figures PATENTED JAN25 I972 SHEET 2 OF 2 switchutilized in the electric space heater shown in FIG. 1;

ELECTRIC SPACE HEATER FIELD OF THE INVENTION This invention relates toheaters, and more particularly, to an improved .electric space or roomheater which is relatively simple and inexpensive to manufacture and isattractive in appearance.-

BACKGROUND OF THE INVENTION In order for an electric space heater to befunctionally operative, attractive in design, and relatively inexpensiveto manufacture, it is desirable that the components of the heater be assimple as possible and cooperate with each other in a manner thatenables rapid assembly. The present invention provides an improvedelectric space heater having the aforementioned desirablecharacteristics.

SUMMARY OF THE INVENTION In the illustrative embodiment of the presentinvention, there is'provided an electric space heater that uses aribbontype resistance wire for generating radiant heat. The resistancewire tends to expand'when being heated and it is carried by spacingmeans mounted upon a reflector. The reflector has a continuously curvingperiphery that is substantially symmetrical about a geometrical axis andmeans are provided for rigidly mounting the reflector adjacent thegeometric axis leaving the greater portion of the reflector fully freeto expand in response to heat from the resistance wire.

The resistance wire is connected through the spacing means tocurvedportions of the reflector that are spaced from the reflector mountingmeans. The reflector mounting means include a sheet metal partwithspaced abutment portions and a central member coupling the abutmentportions. The spaced abutment portions are arranged to symmetricallyengage the outer surface of the reflector with the central member beinglocated at the geometric axis of thereflector. Means are provided forrigidly securing the reflector to the central member so that theengagement 'of the reflector with the abutment portions is a pressureengagement that helps to stabilize the reflector without interferingwith the tendency of the reflector to expand when it is heated.

In the illustrative embodiment of the invention, a protective grill isprovided having a front portion and two side portions extendingrearwardly from the ends of the front portion. The protective grill hasfirst elongated vertical members at the ends .of the front portion andsecond elongated vertical members at the ends of the side portions, withthe ends of the first elongated vertical members being out-tumed andangled with BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS FIG.1 is a front elevational view, partially broken away, of

FIG. 6 is a sectional view taken along the line 6-6 of FIG. 5; and a'FIG. 7 is a fragmentary enlarged sectional view taken along the line7-7 of FIG. 4 and showing the typical insulation mounting of theresistance ribbon on the heaters reflector.

DETAILED DESCRIPTION Referring to the drawings. space heater 10 includesa housing 12 having a back portion 14 and a base portion 16. In theillustrative embodiment, back portion I4 and base portion I6 of thehousing are formed from a single piece of sheet metal. A hand grip I8 isformed by cutting and striking inwardly a part of the back portion l4.Apair of sheet metal pedestals 20 and 22, having rubber-protectedsupport ends 24, are fastened to rigidly to back portion 14 by means ofa pair of spacedsheet metal brackets 32 which are simply secured byscrews or the like to the reflector adjacent its longitudinalcenterline. The two brackets 32 are symmetrically disposed and aredimentimed and positioned so that less than 25 percent of the length ofthe parabolic periphery is rigidly engaged by the bracket means 32 whilethe remaining top and bottom portions of the reflector 28 are free toflex, as will be explained below. 1

Each bracket 32 includes: a transverse mounting flange 33, which abutsand is rigidly fastened to the inside surface of back member 14 of thehousing by a screw or the like; a transverse elongated bight portion 35which operates to space the reflector 28 from the back member I4; a pairof spaced abutment flange portions 35a which are bent so as to beinclined with respect to the longitudinal axis of spacer bight 35 and tobe substantially tangential with respect to the periphery of thereflector; and a securement flange 39. The abutment portions 350 arearranged to symmetrically engage the outer surface of the reflector onopposite sides of the geometric axis thereof. Between the spacedabutment flanges 35a is a central securement flange 39 to which acentral axial portion of the reflector is tied by a connector screw 41.

The securement flange 39 is bent so as to be spaced slightly fromreflector 28 to insure that the spaced flange portions 350 provide asaddlelike and stable support for spaced portions of the reflector 28.In the illustrative embodiment, bracket 32 including flange 33, bightportion 35, abutment flange portions 35a and central securement flange39, is formed as a unitary stamping for economy and for providingstability during use.

The screw 41, which ties the reflector 28 to the central flange 39,provides a tension force on the reflector in the direction toward theback member 14 thereby providing that each of abutment flanges 350 areunder a compressive force from the reflector. In this manner, thereflector is stabilized without the abutment flanges 35a interferingwith the tendency of the reflector to expand when heated.

Reflector 28 has therein a first series of punched slots 360 which arehorizontally aligned upon the top portion of the reflector, and a secondseries of slots 36b which are horizontally aligned along the bottomportion of the reflector. Each of slots 36b is positioned along animaginary vertical line approximately intermediate vertical linesthrough two of slots 36a.

Slots 36a and 366 each receive therein a wire mount spacing clearly inFIGS. 1 and 7. The spacing means 38 adjacent the ends of the reflectorare spaced closer to each other than the centrally located spacing means38 in order for heating element 40 to give a more even heatdistribution.

Reflector 28 defines apertures 44 adjacent the ends of heating element48, through which apertures are passed electrical wire 46 extending fromthe ends of the heating element to a male plug outside the unit (notshown) for connection to a suitable household current supply. A safetyswitch 50, which will be discussed in more detail below, is connected inseries with one of the electrical lines 44. The outer surfaces ofelectrical lines 44 are coated with an electrically insulative materialto prevent electrical contact with the reflector and other metallicportions of the space heater.

A protective grill 54 is positioned to enclose the front and sides ofthe space heater. Protective grill 54 has a front portion 56 which ispositioned in front of the heating element and has side portions 58 and60 which extend rearwardly from the ends of the front portion. Theprotective grill is formed of chrome-plated metal and has elongatedvertical members 61 and 62 at the ends of the front portion andelongated members 64 (the elongated member on the left side of the unitis not shown) at the rearward ends of the side portions 58 and 60. Anadditional elongated vertical member 66 is centrally located withrespect to the front portion 56.

All of the elongated vertical members 61, 62, 64 and 66 are used tosupport a number of elongated transverse grill members 68, which, in theillustrative embodiment of the invention, are shown as horizontalmembers. The elongated vertical members of the grill cooperate with thetop, front and base portions of the housing to effect a simplifiedassembly as is discussed hereinafter.

The housing of the space heater includes a top cover member 70 whichinterconnects with the upper portions of grill 54 without separatefasteners, and which is then fastened through down-tumed flange 70a toback portion 14 by means of only three screws 72. Top cover member 70carries safety switch 50 and can be removed by simply unscrewing screws72 and reversing the manner of assembly by pivoting it to the brokenline position as shown most clearly in FIG. 4. Protective grill 54rigidly interconnects with the base 16 and top 70 by means ofinterfitting of the elongated vertical members 61, 62, 64 and 66 of saidgrill with grooves and apertures in said top and base. Referring to FIG.3, it is seen that base 16 of the unit has in-turned flanges 76 and 78which define therebetween an angled corner groove 80 for receivingtherein" an angled out-turned bottom finger 82 of vertical comer member62. The rear end of the in-turned flange 76 is cut away to be spacedfrom an adjacent in-turned flange of back 14 to define a recess 84 forreceiving the bottom 86 of elongated vertical member 64. The left sideof the base portion 16 (not shown) is syrn'metrical to the right sideillustrated in FIG. 3 and receives the bottom portions of the elongatedvertical members 61 and 64 on the left side of the protective grill.

Top cover member 70, in a manner similar to base portion 16, definescorner grooves for receiving the out-turned and angled top finger 90 ofelongated vertical member 61 and the out-turned and angled top finger 92of elongated vertical member 62, and recesses (not numbered) similar torecess 84 for receiving the upper ends of vertical members 64. Baseportion 16 and top cover member 70 define central apertures 94 and 96,respectively, for receiving the out-turned and angled bottom and top,respectively, of elongated central vertical member 66.

As a result of the construction of the illustrative embodiment of thepresent invention, the unit can be assembled very rapidly, and thecomponents cooperate to form a rigid unit where interlocking elements onthe grill fitting into the base and top of the housing operate to holdthe parts rigidly and require only a minimum number of fasteners 72 tocomplete the assembly. Parabolic reflector 28 is very simple toconstruct and its connection to back portion [4 enables more thanpercent of the reflector to flex in response to heating of heatingelement 40.

In order to prevent the unit from operating if it should fall over, agravity-operable safety switch 50 is utilized. Safety switch 50comprises an electrically insulative support member which is fastened toa bracket 102 by means of a screw 104. Support member 100 has a firstrigid arm 106 fastened thereto and has a flexible arm 108 also fastenedthereto. Rigid arm 106 carries a contact 110 which is normally inengagement with contact 112 carried by flexible arm I08.

Arms 106 and 108 are fonned of electrically conductive material andnormally engage contacts "0 and 112 to cause a series circuit to connecttwo open portions of line 44.

A pivot 116 having a limit member 118 fastened to its end, and isaffixed to rigid arm 106. A weighted operating arm 120 is joumaled topivotal member 116 and comprises an operating member 122 and a weightedmember 124. Operating member 122 is so dimensioned that, when the unittips and weighted member 124 maintains its vertical position resultingfrom the force of gravity, at a predetermined angle of turn the topportion of operating member 122 will cammingly engage the underside offlexible arm 108 to urge contact 112 away from contact 110, therebyopening the circuit. It has been found that this gravity-operable safetyswitch in combination with the unit described above provides a very safeand effective unit, which is relatively inexpensive and simple toconstruct.

Although an illustrative embodiment has been shown and described, it isto be understood that various substitutions and modifications may bemade by those skilled in the art without departing from the spirit andscope of the present invention.

What is claimed is:

l. in an electric space heater that uses a ribbon-type resistance wirefor generating radiant heat, the resistance. wire tending to expand uponbeing heated and being carried by spacing means mounted upon a reflectormeans, the improvement comprising, in combination, a reflector having acontinuous surface that is substantially symmetrical about a geometricalaxis; means for rigidly mounting the reflector adjacent said geometricaxis leaving a portion of the reflector fully free to expand in responseto heat from the resistance wire, the resistance wire being connectedthrough the spacing means to curved portions of the reflector that arespaced from said means for rigidly mounting the reflector, the means forrigidly mounting the reflector including a sheet metal part with spacedabutments that provide flat portions tangent to the reflector and anattachment member spaced between the spaced flat abutments, the spacedabutments being arranged to symmetrically engage the outer surface ofthe reflector with the attachment member being located substantially atthe geometric axis of the reflector; and tension means for securing thereflector to said attachment member so that the engagement of thereflector with the abutment portions is a pressure engagement that helpsto stabilize the reflector without inter-' fering with the tendency ofthe reflector to expand when heated.

2. in an electric space heater as described in claim 1, wherein saidsheet metal part provides a mounting flange adapted to be rigidlysecured to the body of the space heater, a transverse bight portion forspacing the reflector from the body of the heater, and said abutmentportions and attachment member comprising separate flanges spaced fromthe mounting flange with said abutment portions being inclined to lie indifferent planes.

3. A simplified assembly for an electric space heater that is housed ina boxlike enclosure having grill-like sides and front through which heatradiates from an electrically energized emitter, said assemblycomprising, in combination, a unitary base and back upon which theradiant heat emitter is mounted, a grill member formed of spaced rodlikeelements and shaped to provide opposite sidewalls and a front wall forthe boxlike enclosure, a top for the enclosure, recesses defined in thebase and top for receiving rodlike elements of the grill member,certainof the rodlike elements on the grill member being angled withrespect to the plane of the surfaces generally defined by the grill soas to interlock with the recesses on the base and top without use offasteners, the angled rodlike elements being located at the junctionsbetween the sidewalls and front wall of the grill member and each beingangled outwardly with respect to both walls that join at said junction,the top having means arranged to interfit with the back to apply tensionto the grill member to effect a rigid holding of the rodlike elements onthe grill member when the top is assembled, and securing means forselectively securing the top to the back to hold the enclosure togetherwithout rattling.

4. An assembly as in claim 3, wherein the securing means are a pluralityof screws, which permits assembly or disassembly with a single tool.

5. An assembly as in claim 3, wherein the unitary back and base areformed of sheet metal with in-turned flanges thereon shaped and arrangedto define angled grooves between pairs of flanges for receivingthereinto the angled rodlike elements of the grill member.

6. An electric heater as described in claim 3, further including meansfor connecting said emitter to a current supply including a safetyswitch carried by the top of the enclosure and wired in series with anelectrically conductive line, said switch having a pair of normallyclosed contacts and means for opening said contacts when the spaceheater tips to a predetermined angle with respect to its normal uprightposition.

7. In an electric space heater as described in claim 6, wherein saidsafety switch includes a support member, a first rigid arm fastened tosaid support member and carrying a contact and a weighted member, meanspivotally connecting said weighted member to said rigid arm, a secondflexible arm fastened to said support member and carrying a contact thatis normally in engagement with the rigid arm contact when the spaceheater is in its normal upright position, saidaweighted arm beingdimensioned to cam said flexible arm away from said rigid arm when saidweighted member is pivoted as a result of tipping the space heater,whereby said rigid arm contact will disengage said flexible arm contact.

8. A simplified assembly for an electric space heater that is housed ina boxlike enclosure having grill-like sides and front through which heatradiates from an electrically energized emitter, said assemblycomprising, in combination, a unitary base and back upon which theradiant heat emitter is mounted, a grill member formed of spaced rodlikeelements and shaped to provide opposite sidewalls and a front wall forthe boxlike enclosure, a top for the enclosure, recesses defined in thebase and top for receiving rodlike elements of the grill member, certainof the rodlike elements on the grill member being angled with respect tothe plane of the surfaces generally defined by the grill so as tointerlock with the recesses on the base and top without use offasteners, the unitary back and base being formed of sheet metal within-turned flanges thereon shaped and arranged to define angled groovesbetween pairs of flanges for receiving thereinto the angled rodlikeelements of the grill member, the top having means arranged to interfitwith the back to apply tension to the grill member to effect arigid-holding of the rodlike elements on the grill member when the topis assembled, and securing means for selectively securing the top to theback to hold the enclosure together without rattling.

1. In an electric space heater that uses a ribbon-type resistance wirefor generating radiant heat, the resistance wire tending to expand uponbeing heated and being carried by spacing means mounted upon a reflectormeans, the improvement comprising, in combination, a reflector having acontinuous surface that is substantially symmetrical about a geometricalaxis; means for rigidly mounting the reflector adjacent said geometricaxis leaving a portion of the reflector fully free to expand in responseto heat from the resistance wire, the resistance wire being connectedthrough the spacing means to curved portions of the reflector that arespaced from said means for rigidly mounting the reflector, the means forrigidLy mounting the reflector including a sheet metal part with spacedabutments that provide flat portions tangent to the reflector and anattachment member spaced between the spaced flat abutments, the spacedabutments being arranged to symmetrically engage the outer surface ofthe reflector with the attachment member being located substantially atthe geometric axis of the reflector; and tension means for securing thereflector to said attachment member so that the engagement of thereflector with the abutment portions is a pressure engagement that helpsto stabilize the reflector without interfering with the tendency of thereflector to expand when heated.
 2. In an electric space heater asdescribed in claim 1, wherein said sheet metal part provides a mountingflange adapted to be rigidly secured to the body of the space heater, atransverse bight portion for spacing the reflector from the body of theheater, and said abutment portions and attachment member comprisingseparate flanges spaced from the mounting flange with said abutmentportions being inclined to lie in different planes.
 3. A simplifiedassembly for an electric space heater that is housed in a boxlikeenclosure having grill-like sides and front through which heat radiatesfrom an electrically energized emitter, said assembly comprising, incombination, a unitary base and back upon which the radiant heat emitteris mounted, a grill member formed of spaced rodlike elements and shapedto provide opposite sidewalls and a front wall for the boxlikeenclosure, a top for the enclosure, recesses defined in the base and topfor receiving rodlike elements of the grill member, certain of therodlike elements on the grill member being angled with respect to theplane of the surfaces generally defined by the grill so as to interlockwith the recesses on the base and top without use of fasteners, theangled rodlike elements being located at the junctions between thesidewalls and front wall of the grill member and each being angledoutwardly with respect to both walls that join at said junction, the tophaving means arranged to interfit with the back to apply tension to thegrill member to effect a rigid holding of the rodlike elements on thegrill member when the top is assembled, and securing means forselectively securing the top to the back to hold the enclosure togetherwithout rattling.
 4. An assembly as in claim 3, wherein the securingmeans are a plurality of screws, which permits assembly or disassemblywith a single tool.
 5. An assembly as in claim 3, wherein the unitaryback and base are formed of sheet metal with in-turned flanges thereonshaped and arranged to define angled grooves between pairs of flangesfor receiving thereinto the angled rodlike elements of the grill member.6. An electric heater as described in claim 3, further including meansfor connecting said emitter to a current supply including a safetyswitch carried by the top of the enclosure and wired in series with anelectrically conductive line, said switch having a pair of normallyclosed contacts and means for opening said contacts when the spaceheater tips to a predetermined angle with respect to its normal uprightposition.
 7. In an electric space heater as described in claim 6,wherein said safety switch includes a support member, a first rigid armfastened to said support member and carrying a contact and a weightedmember, means pivotally connecting said weighted member to said rigidarm, a second flexible arm fastened to said support member and carryinga contact that is normally in engagement with the rigid arm contact whenthe space heater is in its normal upright position, said weighted armbeing dimensioned to cam said flexible arm away from said rigid arm whensaid weighted member is pivoted as a result of tipping the space heater,whereby said rigid arm contact will disengage said flexible arm contact.8. A simplified assembly for an electric space heater that is housed ina boxlike enclosure having grIll-like sides and front through which heatradiates from an electrically energized emitter, said assemblycomprising, in combination, a unitary base and back upon which theradiant heat emitter is mounted, a grill member formed of spaced rodlikeelements and shaped to provide opposite sidewalls and a front wall forthe boxlike enclosure, a top for the enclosure, recesses defined in thebase and top for receiving rodlike elements of the grill member, certainof the rodlike elements on the grill member being angled with respect tothe plane of the surfaces generally defined by the grill so as tointerlock with the recesses on the base and top without use offasteners, the unitary back and base being formed of sheet metal within-turned flanges thereon shaped and arranged to define angled groovesbetween pairs of flanges for receiving thereinto the angled rodlikeelements of the grill member, the top having means arranged to interfitwith the back to apply tension to the grill member to effect a rigidholding of the rodlike elements on the grill member when the top isassembled, and securing means for selectively securing the top to theback to hold the enclosure together without rattling.